In the production process of semiconductor integrated circuit devices, after a great number of integrated circuits are formed on a wafer composed of, for example, silicon, a probe test that basic electrical properties of each of these integrated circuits are inspected, thereby sorting defective integrated circuits is generally conducted. This wafer is then diced, thereby forming semiconductor chips. Such semiconductor chips are housed and sealed in respective proper packages. Each of the packaged semiconductor integrated circuit devices is further subjected to a burn-in test that electrical properties thereof are inspected under a high-temperature environment, thereby sorting semiconductor integrated circuit devices having latent defects.
In such electrical inspection of integrated circuits, such as probe test or burn-in test, a probe card having inspection electrodes arranged in accordance with a pattern corresponding to a pattern of electrodes to be inspected is in use for electrically connecting each of the electrodes to be inspected in an object of inspection to a tester. As such a probe card, has heretofore been used that, on which inspection electrodes (inspection probes) each composed of a pin or blade are arranged.
By the way, in the probe test conducted for integrated circuits formed on a wafer, a method that a wafer is divided into a plurality of areas, in each of which, for example, 16 integrated circuits have been formed, a probe test is performed collectively on all the integrated circuits formed in an area, and the probe test is successively performed collectively on the integrated circuits formed in other areas has heretofore been adopted. In recent years, there has been a demand for collectively performing a probe test on a greater number of integrated circuits for the purpose of improving inspection efficiency and reducing inspection cost.
In the burn-in test on the other hand, it takes a long time to individually conduct electrical inspection of a great number of integrated circuit devices because each integrated circuit device that is an object of inspection is fine, and its handling is inconvenient, whereby inspection cost becomes considerably high. From such reasons, in recent years, there has been proposed a WLBI (Wafer Level Burn-in) test in which the burn-in test is performed collectively on a great number of integrated circuits formed on a wafer.
In order to produce a probe card used in such a probe test or WLBI test, it is however necessary to arrange a very great number of inspection probes, so that such a probe card is extremely expensive. In addition, when the number of electrodes to be inspected is great, and the pitch thereof is fine, it is difficult to produce the probe card itself.
From such reasons, there has been recently proposed a probe card having a circuit board for inspection, on one surface of which a plurality of inspection electrodes have been formed in accordance with a pattern corresponding to a pattern of electrodes to be inspected, an anisotropically conductive elastomer sheet arranged on one surface of this circuit board for inspection, in which a plurality of conductive parts each extending in a thickness-wise direction of the sheet have been formed in accordance with a pattern corresponding to the pattern of the electrodes to be inspected, and a sheet-like probe arranged on this anisotropically conductive elastomer sheet (for example, Patent Art. 1.). The sheet-like probe in this probe card is constructed by an insulating sheet, a plurality of electrode structures arranged in this insulating sheet in accordance with a pattern corresponding to the pattern of the electrodes to be inspected and each extending through in a thickness-wise direction of the insulating sheet, and a ring-like holding member provided at a peripheral edge portion of the insulating sheet and composed of, for example, a ceramic.
When a wafer that is an object of inspection is of a large size as at least 8 inches in diameter, and the number of electrodes to be inspected thereof is at least 5,000, particularly at least 10,000, however, a pitch between the electrodes to be inspected in each integrated circuit is extremely small, so that the anisotropically conductive elastomer sheet in the above probe card involves the following problems.    (1) It is necessary to use an anisotropically conductive elastomer sheet having a considerably large area in order to inspect a wafer having a diameter of, for example, 8 inches (about 20 cm) collectively or by dividing it into areas, in each of which a plurality of integrated circuits have been formed. However, it is extremely difficult to surely produce such an anisotropically conductive elastomer sheet because each conductive part is fine, and a proportion of the surface area of the conductive parts to the surface of the anisotropically conductive elastomer sheet is low though the area of the anisotropically conductive elastomer sheet is considerably large. Accordingly, the yield in the production of the anisotropically conductive elastomer sheet is lowered. As a result, the production cost of the anisotropically conductive elastomer sheet is increased, and in turn the inspection cost is increased.    (2) The coefficient of linear thermal expansion of a material making up the wafer, for example, silicon is about 3.3×10−6/K. On the other hand, the coefficient of linear thermal expansion of a material making up the anisotropically conductive elastomer sheet, for example, silicone rubber is about 2.2×10−4/K. When the material (for example, silicon) making up the integrated circuit devices that are the object of inspection and the material (for example, silicone rubber) making up the anisotropically conductive elastomer sheet are greatly different from each other in the coefficient of linear thermal expansion as described above, positional deviation occurs between the conductive parts of the anisotropically conductive elastomer sheet and the electrodes to be inspected of the integrated circuit devices when they are subjected to thermal hysteresis by temperature change. As a result, an electrically connected state is changed, and it is thus difficult to retain a stably connected state.
In order to solve the above-described problems, there has been proposed a anisotropically conductive connector composed of a frame plate, in which a plurality of openings have been formed corresponding to electrode regions, in which electrodes to be inspected of integrated circuits in a wafer that is an object of inspection have been formed, and a plurality of elastic anisotropically conductive films arranged in the respective openings in this frame plate so as no close the openings (see, for example, Patent Art. 2).
On the other hand, the sheet-like probe in the above-described probe card involves the following problems.
In the sheet-like probe of the probe card, the insulating sheet is fixed to a holding member in a state that tension has been applied thereto in order to prevent or inhibit the thermal expansion of the insulating sheet.
However, at is extremely difficult to evenly apply the tension to the insulating sheet in all directions of the plane direction thereof, and a balance of the tension applied to the insulating sheet is changed by forming the electrode structures. As a result, the insulating sheet comes to have anisotropy on thermal expansion, so that even when the thermal expansion in one direction of the plane direction can be inhibited, thermal expansion in other directions intersecting said one direction cannot be inhibited. Accordingly, the positional deviation between the electrode structures and the electrodes to be inspected cannot be surely prevented when they are subjected to thermal hysteresis by temperature change.
In addition, in order to fix the insulating sheet to the holding member in the state that the tension has been applied thereto, a complicated step of bonding the insulating sheet to the holding member under heating is required, so that a problem that increase in production cost is incurred arises.
In order to solve the above problems, the present applicant proposed a sheet-like probe composed of a frame plate, in which a plurality of openings have been formed corresponding to electrode regions, in which electrodes to be inspected of integrated circuits in a wafer, which is an object of inspection, have been formed, and a plurality of contact films arranged on and supported by one surface of the frame plate so as to close the respective openings of the frame plate, each of said contact films being composed of an insulating film and electrode structures arranged in the insulating film, and a probe card equipped with this sheet-like probe and the above-described anisotropically conductive connector (see Japanese Patent Application No. 2004-305956).
However, it has been found that such a probe card involves the following problems.
In order to achieve good electrical connection in a connecting operation between a wafer, which is an object of inspection, and the probe card, it is essential to pressurize the conductive parts of the anisotropically conductive connector in the probe card in a thickness-wise direction of the connector by back-surface electrode parts of the sheet-like probe so as to sufficiently compress the conductive parts.
As illustrated in FIG. 52, however, the frame plate 81 in the sheet-like probe 80 is present between the contact film 85 in the sheet-like probe 80 and the elastic anisotropically conductive film 95 in the anisotropically conductive connector 90, whereby the frame plate 81 of the sheet-like probe 80 comes into contact with the elastic anisotropically conductive film 95 of the anisotropically conductive connector 90 when the electrode structures 86 of the sheet-like probe 80 are pressurized, so that the conductive parts 96 of the elastic anisotropically conductive film 95 cannot be surely compressed in the thickness-wise direction of the film by the back-surface electrode parts 87 of the electrode structures 86. As a result, it is difficult to surely achieve a good electrically connected state.    Patent Art. 1: Japanese Patent Application Laid-Open No. 2001-15565;    Patent Art. 2: Japanese Patent Application Laid-Open No. 2002-184821